The present invention relates generally to an imaging apparatus and layers for components thereof, and for use in offset printing or ink jet printing apparatuses. The layers herein are useful for many purposes including layers for transfer components, including transfix or transfuse components, imaging components, and like components. More specifically, the present invention relates to layers comprising nano-size fillers. The layers of the present invention may be useful in components used in combination with ink, dye or pigment-based materials. In embodiments, the layers can be used in combination with phase change inks such as solid inks, gel-based inks, ultraviolet curable inks, and other phase-change inks.
Ink jet printing systems using intermediate transfer, transfix or transfuse members are well known, such as that described in U.S. Pat. No. 4,538,156. Generally, the printing or imaging member is employed in combination with a printhead. A final receiving surface or print medium is brought into contact with the imaging surface after the image has been placed thereon by the nozzles of the printhead. The image is then transferred and fixed to a final receiving surface.
More specifically, the phase-change ink imaging process begins by first applying a thin liquid, such as, for example, silicone oil, to an imaging member surface. The solid or hot melt ink is placed into a heated reservoir where it is maintained in a liquid state. This highly engineered ink is formulated to meet a number of constraints, including low viscosity at jetting temperatures, specific visco-elastic properties at component-to-media transfer temperatures, and high durability at room temperatures. Once within the printhead, the liquid ink flows through manifolds to be ejected from microscopic orifices through use of proprietary piezoelectric transducer (PZT) printhead technology. The duration and amplitude of the electrical pulse applied to the PZT is very accurately controlled so that a repeatable and precise pressure pulse can be applied to the ink, resulting in the proper volume, velocity and trajectory of the droplet. Several rows of jets, for example four rows, can be used, each one with a different color. The individual droplets of ink are jetted onto the liquid layer on the imaging member. The imaging member and liquid layer are held at a specified temperature such that the ink hardens to a ductile visco-elastic state.
After depositing the image, a print medium is heated by feeding it through a preheater and into a nip formed between the imaging member and a pressure member, either or both of which can also be heated. A high durometer synthetic pressure member is placed against the imaging member in order to develop a high-pressure nip. As the imaging member rotates, the heated print medium is pulled through the nip and is pressed against the deposited ink image with the help of a pressure member, thereby transferring the ink to the print medium. The pressure member compresses the print medium and ink together, spreads the ink droplets, and fuses the ink droplets to the print medium. Heat from the preheated print medium heats the ink in the nip, making the ink sufficiently soft and tacky to adhere to the print medium. When the print medium leaves the nip, stripper fingers or other like members, peel it from the printer member and direct it into a media exit path.
To optimize image resolution, the transferred ink drops should spread out to cover a predetermined area, but not so much that image resolution is compromised or lost. The ink drops should not melt during the transfer process. To optimize printed image durability, the ink drops should be pressed into the paper with sufficient pressure to prevent their inadvertent removal by abrasion. Finally, image transfer conditions should be such that nearly all the ink drops are transferred from the imaging member to the print medium. Therefore, it is desirable that the imaging member has the ability to transfer the image to the media sufficiently.
The imaging member is multi-functional. First, the ink jet printhead prints images on the imaging member, and thus, it is an imaging member. Second, after the images are printed on the imaging member, they can then transfixed or transfused to a final print medium. Therefore, the imaging member provides a transfix or transfuse function, in addition to an imaging function.
In order to ensure proper transfer and fusing of the ink off the imaging member to the print medium, certain nip temperature, pressure and compliance are required. Unlike laser printer imaging technology in which solid fills are produced by sheets of toner, the solid ink is placed on the imaging member one pixel at a time and the individual pixels must be spread out during the transfix process to achieve a uniform solid fill. Also, the secondary color pixels on the imaging member are physically taller than the primary color pixels because the secondary pixels are produced from two primary pixels. Therefore, compliance in the nip is required to conform around the secondary pixels and to allow the primary pixel neighbors to touch the media with enough pressure to spread and transfer. The correct amount of temperature, pressure and compliance is required to produce acceptable image quality.
Currently, the imaging member useful for solid inks or phase change inks comprises anodized aluminum. This member operates at about 57° C. to about 64° C. and can be used with a heater that preheats the print media prior to entering the nip. Otherwise, the imaging member may include a heater associated therewith. The heater may be associated anywhere on the offset printing apparatus. The current aluminum-imaging member has several drawbacks. A high nip load of up to about 770 pounds is needed for transfix or transfuse operations. Further, because of the high nip load, bulky mechanisms and supporting structures are needed, resulting in increased printer weight and cost. One example is that a fairly complex two-layer pressure roller is needed. In addition, the first copy out time is unacceptable because of the bulky weight. Moreover, low cohesive failure temperature is another drawback to use of an anodized aluminum drum.
Several coatings for the imaging member have been suggested. Examples are listed below.
U.S. Pat. No. 5,092,235 discloses a pressure fixing apparatus for ink jet inks having 1) outer shell of rigid, non-compliant material such as steel, or polymer such as acetal homopolymer or Nylon 6/6 and 2) an underlayer of elastomer material having a hardness of about 30 to 60, or about 50 to 60.
U.S. Pat. No. 5,195,430 discloses a pressure fixing apparatus for ink jet inks having 1) outer shell of rigid, non-compliant material such as steel, or polymer such as acetal homopolymer or Nylon 6/6 and 2) an underlayer of elastomer material having a hardness of about 30 to 60, or about 50 to 60, which can be polyurethane (VIBRATHANE, or REN:C:O-thane).
U.S. Pat. No. 5,389,958 discloses an intermediate transfer member/image receiving member having a surface of metal (aluminum, nickel, iron phosphate), elastomers (fluoroelastomers, perfluoroelastomers, silicone rubber, polybutadiene), plastics (polyphenylene sulfide), thermoplastics (polyethylene, polyamide (nylon), FEP), thermosets (metals, ceramics), and a pressure roller with elastomer surface.
U.S. Pat. No. 5,455,604 discloses a fixing mechanism and pressure wheels, wherein the pressure wheels can be comprised of a steel or plastic material such as DELRIN. Image-receiving drum 40 can be a rigid material such as aluminum or stainless steel with a thin shell mounted to the shaft, or plastic.
U.S. Pat. No. 5,502,476 teaches a pressure roller having a metallic core with elastomer coating such as silicones, urethanes, nitriles, or EPDM, and an intermediate transfer member surface of liquid, which can be water, fluorinated oils, glycol, surfactants, mineral oil, silicone oil, functional oils such as mercapto silicone oils or fluorinated silicone oils or the like, or combinations thereof.
U.S. Pat. No. 5,614,933 discloses an intermediate transfer member/image receiving member having a surface of metal (aluminum, nickel, iron phosphate), elastomers (fluoroelastomers, perfluoroelastomers, silicone rubber, polybutadiene), plastics (polyphenylene sulfide), thermoplastics (polyethylene, polyamide (nylon), FEP), thermosets (metals, ceramics), or polyphenylene sulfide loaded with PTFE, and a pressure roller with elastomer surface.
U.S. Pat. No. 5,790,160 discloses an intermediate transfer member/image receiving member having a surface of metal (aluminum, nickel, iron phosphate), elastomers (fluoroelastomers, perfluoroelastomers, silicone rubber, polybutadiene), plastics (polyphenylene sulfide), thermoplastics (polyethylene, polyamide (nylon), FEP), thermosets (metals, ceramics), or polyphenylene sulfide loaded with PTFE, and a pressure roller with elastomer surface.
U.S. Pat. No. 5,805,191 an intermediate transfer member/image receiving member having a surface of metal (aluminum, nickel, iron phosphate), elastomers (fluoroelastomers, perfluoroelastomers, silicone rubber, polybutadiene), plastics (polyphenylene sulfide), thermoplastics (polyethylene, polyamide (nylon), FEP), thermosets (metals, ceramics), or polyphenylene sulfide loaded with PTFE, and an outer liquid layer of liquid, which can be water, fluorinated oils, glycol, surfactants, mineral oil, silicone oil, functional oils such as mercapto silicone oils or fluorinated silicone oils or the like, or combinations thereof.
U.S. Pat. No. 5,808,645 discloses a transfer roller having a metallic core with elastomer covering of silicone, urethanes, nitriles, and EPDM.
U.S. Pat. No. 6,196,675 B1 discloses separate image transfer and fusing stations, wherein the fuser roller coatings can be silicones, urethanes, nitrites and EPDM.
U.S. Pat. No. 5,777,650 discloses a pressure roller having an elastomer sleeve, and an outer coating that can be metals, (aluminum, nickel, iron phosphate), elastomers (fluoroelastomers, perfluoroelastomers, silicone rubber, polybutadiene), plastics (polyphenylene sulfide with PTFE filler), thermoplastics (polyethylene, polyamide (nylon), FEP), thermosets (acetals, ceramics). Preferred is anodized aluminum.
In addition, many different types of outer coatings for transfer members, fuser members, and intermediate transfer members have been used in the electrostatographic arts using powder toner, but not with liquid inks or phase change inks. Several examples are listed herein.
U.S. Pat. No. 5,361,126 discloses an imaging apparatus including a transfer member including a heater and pressure-applying roller, wherein the transfer member includes a fabric substrate and an impurity-absorbent material as a top layer. The impurity-absorbing material can include a rubber elastomer material.
U.S. Pat. No. 5,337,129 discloses an intermediate transfer component comprising a substrate and a ceramer or grafted ceramer coating comprised of integral, interpenetrating networks of haloelastomer, silicon oxide, and optionally polyorganosiloxane.
U.S. Pat. No. 5,340,679 discloses an intermediate transfer component comprised of a substrate and thereover a coating comprised of a volume grafted elastomer, which is a substantially uniform integral interpenetrating network of a hybrid composition of a fluoroelastomer and a polyorganosiloxane.
U.S. Pat. No. 5,480,938 describes a low surface energy material comprising a volume grafted elastomer which is a substantially uniform integral interpenetrating network of a hybrid composition of a fluoroelastomer and a polyorganosiloxane, the volume graft having been formed by dehydrofluorination of fluoroelastomer by a nucleophilic dehydrofluorinating agent, followed by a hydrosilation reaction, addition of a hydrogen functionally terminated polyorganosiloxane and a hydrosilation reaction catalyst
U.S. Pat. No. 5,366,772 describes a fuser member comprising a supporting substrate, and a outer layer comprised of an integral interpenetrating hybrid polymeric network comprised of a haloelastomer, a coupling agent, a functional polyorganosiloxane and a crosslinking agent.
U.S. Pat. No. 5,456,987 discloses an intermediate transfer component comprising a substrate and a titamer or grafted titamer coating comprised of integral, interpenetrating networks of haloelastomer, titanium dioxide, and optionally polyorganosiloxane.
U.S. Pat. No. 5,848,327 discloses an electrode member positioned near the donor member used in hybrid scavengeless development, wherein the electrode members have a composite haloelastomer coating.
U.S. Pat. No. 5,576,818 discloses an intermediate toner transfer component including: (a) an electrically conductive substrate; (b) a conformable and electrically resistive layer comprised of a first polymeric material; and (c) a toner release layer comprised of a second polymeric material selected from the group consisting of a fluorosilicone and a substantially uniform integral interpenetrating network of a hybrid composition of a fluoroelastomer and a polyorganosiloxane, wherein the resistive layer is disposed between the substrate and the release layer.
U.S. Pat. No. 6,035,780 discloses a process for forming a layer on a component of an electrostatographic apparatus, including mixing a first fluoroelastomer and a polymeric siloxane containing free radical reactive functional groups, and forming a second mixture of the resulting product with a mixture of a second fluoroelastomer and a second polysiloxane compound.
U.S. Pat. No. 5,537,194 discloses an intermediate toner transfer member comprising: (a) a substrate; and (b) an outer layer comprised of a haloelastomer having pendant hydrocarbon chains covalently bonded to the backbone of the haloelastomer.
U.S. Pat. No. 5,753,307 discloses fluoroelastomer surfaces and a method for providing a fluoroelastomer surface on a supporting substrate which includes dissolving a fluoroelastomer; adding a dehydrofluorinating agent; adding an amino silane to form a resulting homogeneous fluoroelastomer solution; and subsequently providing at least one layer of the homogeneous fluoroelastomer solution to the supporting substrate.
U.S. Pat. No. 5,840,796 describes polymer nanocomposites including a mica-type layered silicate and a fluoroelastomer, wherein the nanocomposite has a structure selected from the group consisting of an exfoliated structure and an intercalated structure.
U.S. Pat. No. 5,846,643 describes a fuser member for use in an electrostatographic printing machine, wherein the fuser member has at least one layer of an elastomer composition comprising a silicone elastomer and a mica-type layered silicate, the silicone elastomer and mica-type layered silicate form a delaminated nanocomposite with silicone elastomer inserted among the delaminated layers of the mica-type layered silicate.
U.S. Pat. No. 5,933,695 discloses a rapid wake up fuser member comprising a substrate, a heat transmissive layer provided on the substrate and having a silicone material and a Q-resin, and a toner release layer comprising a polymer and provided on the heat transmissive layer.
U.S. Pat. No. 4,853,737 discloses rollers having an outer layer comprising a cured fluoroelastomer containing pendant polydiorganosiloxane units that are covalently bonded to the backbone of the fluoroelastomer.
Some elastomer coatings have been shown to provide a multi-functional imaging member for use with phase change ink printing machines, which has the ability to receive an image, and either transfer, or transfer and fuse the image to a print medium. In addition, the imaging member having embodiments of elastomer coatings, has also been shown to be thermally stable for conduction for fusing or fixing. Moreover, the imaging member having certain elastomer coatings has been shown to have a relatively low nip load, in order to decrease the weight and cost of the printing machine, and in order to provide an acceptable first copy out time. Also, the elastomers enable low load, high temperature process for low unit manufacturing costs, and high speed printing. Further, some elastomers have been shown to increase print quality.
However, some disadvantages of the elastomeric imaging member coatings include the life shortfall versus the hard anodized component counterpart. The shortfall could be due to coating wear, peel-off from the imaging member substrate, external scratches, or other reasons.
Therefore, it is desired to provide a coating for an imaging member, which has the above superior qualities of elastomeric coatings, and which has an increased wear and life. It is further desired to provide improved surface wear resistance and improved gloss maintenance life against paper abrasion. In addition, it is desired to provide a coating with control over surface roughness and lower coefficient of friction.